Motivated by such a profound view on model-dependent realism [1]}, here we turn to a particular phenomenon well-known in different subfield of nature. It is the energy loss of charged projectiles [2]} in matter, and the characterization of the slowing down by an
average retarding force experienced by heavy intruders. Evidently, the phenomenon prescribes a quantum (wave) mechanical consideration of electrons in the target material. Furthermore, a retarding-force interpretation of the energy loss per unit path length (\(dE/dx\) ) for ions requires the calculation of expectation values of the force operator (gradient of an external potential) considering complete sets for electron states in order to quantify an observable.
